Network operating system with distributed data architecture

ABSTRACT

A network operating system NOS for an agile optical network with a plurality of mesh interconnected switching nodes, manages the network using an object-oriented network information model. The model is common to all applications requiring the data stored in the network managed information base. The core model can be expanded for serving specific application areas. The NOS is organized in layers, at the optical module level, connection level and network level. A distributed topology server DTS organizes the physical, logical and topological data defining all network entities as managed objects MO and topology objects TO for constructing a complete network view. The network information model associates a network element NE information model, specified by managed objects MO and a topological information model, specified by topology objects TO. The MOs are abstract specific NE data that define network implementation details and do not include any topological data, while the TOs abstract specific topological data for defining a trail established within the network, and do not include any NE data. The models are associated in a minimal number of points to construct the model of a trial in response to a connection request.

PRIORITY PATENT APPLICATION

Continuation in part of U.S. patent Application “Network operatingsystem with topology autodiscovery” (Emery et al.), Ser. No. 10/163,939,filed on Jun. 6, 2002 assigned to Innovance, Inc.

RELATED PATENT APPLICATIONS

U.S. patent application Ser. No. 09/876,391, “Architecture For APhotonic Transport Network”, (Roorda et al.), filed Jun. 7, 2001.

I U.S. patent application “Method for Engineering Connections in aDynamically Reconfigurable Photonic Switched Network” (Zhou et al.) Ser.No. NA, filed May 21, 2002.

U.S. patent application Ser. No. 09/909,265, “Wavelength Routing andSwitching Mechanism for a Photonic Transport Network”, Smith et al.,filed Jul. 19, 2001, assigned to Innovance Inc.

These patent applications are incorporated herein by reference.

FIELD OF THE INVENTION

The invention resides in the field of optical communication networks,and is directed in particular to a network operating system withdistributed data architecture.

BACKGROUND OF THE INVENTION

Due to increased competition and eroding revenue margins, serviceproviders are demanding better yields from their network infrastructure.Thus, bandwidth-on-demand for event driven traffic, or creation ofbandwidth brokering services are just a few of the new optical layerservices that can be created. Attributes such as protection level,latency, priority, transparency, and diversity may also be used todefine optical services. These need to be either general characteristicsof the network or specific characteristics of a connection. As such,class of service (CoS) considerations need to be taken into account bothwhen planning a network, when routing an individual connection, and whencollecting the revenue.

These demands have exposed a number of weaknesses with respect to thecurrent optical networks and their mode of operation.

Traditional WDM (wavelength division multiplexed) network has apoint-to-point configuration, with electrical cross-connects (EXC)provided at all switching nodes. This network architecture allows fairlylimited optical layer service offerings and is also very difficult toscale. Thus, a point-to-point architecture does not have the ability toturn up/down bandwidth rapidly, or/and to provide bandwidth optimizedfor the data layer needs, even if the equipment for the new service isin place.

As a result, there is a trend to transit from the point-to-pointconfigurations to a new architecture, where the connections are routed,switched and monitored independently. To enable automatic or‘point-and-click’, dynamic connection set-up and removal, the networkmanagement must avail itself with a very accurate inventory of allcurrent network resources at a finer granularity (i.e. at the opticalmodule level) than in current networks. This information must alsoinclude the real-time allocation of the network resources to thecurrently active connections. Furthermore, in this type of network, thetraditional manual span-by-span engineering cannot be performed as thechannels sharing the same fiber do not have the same origin, destinationand network traversing history. Rather, the network management must beprovided with automatic end-to-end optical path engineering, whichrequires availability of large amount of performance and topology data.Thus, the network management must keep an updated view of the actual andestimated optical performance for all optical spans, links, paths in thecontext of connections being set-up and torn down arbitrarily.

In short, the network management of an agile optical network needs to beprovided with a means to collect, update, and maintain topology andperformance information and with the ability to fast retrieve it whenneeded. This in turn implies changes in the type and granularity of thenetwork data that is kept, and also in the way this data is organized.

SUMMARY OF THE INVENTION

It is an object of the invention to provide an optical network with adistributed data architectures that enables dynamic reconfiguration ofnetwork connectivity, flexibility and scalability.

Accordingly, the invention provides an object-oriented networkinformation mode for an agile optical network having a plurality ofinterconnected switching nodes, comprising: a core network informationmodel that is common to all applications requiring the informationprovided by the model; and an extension to the core network informationmodel for serving specific application areas.

In accordance with another aspect of the invention, a network operatingsystem NOS for an agile optical network having a plurality ofinterconnected switching nodes comprises: at an embedded layer organizedin embedded domains under control of a shelf processor SP, a SP forcontrolling operation of all optical modules in the embedded domainbased on physical, logical and topological data reported by the opticalmodules; at a network services control NSC layer organized in spans ofcontrol SOC under control of a respective NSC, a NSC for controllingoperation all network elements NE in the SOC based on physical, logicaland topological data reported by the NEs; and a distributed topologyserver DTS for organizing the data as managed objects MO and topologicalobjects TO based on the physical, logical and topological data forconstructing a complete network view.

Still further, the invention is directed to a network element NEinformation model defined by a plurality of managed elements MO, whereeach MO comprises specific data describing a respective network entity,and a list with the classes of all MOs it contains, affects, supportsand inherits from, for modeling the NEs that implement the network andspecifically not to model connections across the network in which the NEparticipates, the NE information model comprising: an equipment holderclass, containing k equipment holder MOs;an equipment class containing Iequipment MOs, each containing m software objects, and inheriting fromone of an equipment holder object and a circuit pack object; and atermination point class, containing n termination point objects, eachinheriting from one of a trail termination point TTP object thatspecifies a potential termination of an optical path and a connectiontermination point CTP object that specifies a potential termination of aconnection.

According to a further aspect of the invention, an MIB of an agileoptical network, provides a layered topology information model formodeling potential connections over the network and specifically not tomodel the network elements that implement the network, the topologyinformation model comprising: a topological components class includinglayer network objects, access group objects, subnetwork objects, linkobjects and link end objects; a transport entities class including trailobjects, subnetwork connection objects, and link connection objects; anda termination point class including trail termination point TTP objects,a TTP object for specifying the ends of a trail object and connectiontermination point CTP objects, a CTP object for specifying the ends of alink connection object.

In another aspect, the invention is concerned with a high levelsignaling architecture for establishing communication between aninternal network domain encompassing an agile optical network and aclient domain, comprising: an internal signaling network, operating overa UNI-N interface for supporting all management and control operationsthat enable automatic set-up and removal of end-end trails within theagile optical network; a NMS-UNI interface for enabling network-levelapplications including performance, fault, configuration, securitymanagement and common applications, as well as distribution of addressesto all network entities on the internal signaling network; and a UNIsignaling interface between the internal signaling network and a userterminal in the client domain for transmitting a connection request andspecifying a class of service for the request.

In order to model a call in an agile optical network meshinterconnecting a plurality of switching nodes, the network having a R&Scontrol for calculating end-to-end trails and a MIB holding a networkinformation model, the method according to the invention comprises thesteps of: (a) receiving a connection request specifying a source node, adestination node, and a class of service CoS; (b) creating a call ID foridentifying the call, and a trail ID for identifying a trail between thesource and destination node, and requesting the R&S control to provideexplicit trail data including the nodes along the trail; (c) reservingthe trail; and (d) activating the trail for establishing the call overthe trail.

The distributed data architecture according to the invention allowsmaintaining and organizing a large amount of performance and topologyinformation at the optical module granularity, for enabling dynamicreconfiguration of network connections.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, features and advantages of theinvention will be apparent from the following more particulardescription of the preferred embodiments, as illustrated in the appendeddrawings, where:

FIG. 1 is an example of a fragment of an agile optical network where thepresent invention may be used;

FIG. 2 shows the computing platforms of the network operating system ofthe agile optical network of FIG. 1;

FIG. 3 illustrates the residence of various managed objects in thenetwork operating system of FIG. 2;

FIG. 4A shows the network element information model;

FIG. 4B shows a generic managed element;

FIG. 5A illustrates the relationship between the connection terminationpoints and the circuit pack objects;

FIG. 5B shows circuit pack adjacency;

FIG. 5C is an example of modeling regenerator and access pools for a 3×3switching node;

FIGS. 6 a-6 f provide the definition of the terms used for the networktopology model according to the invention. FIG. 6 a shows the topologycomponents, FIGS. 6 b-6 c show how a detailed network (FIG. 6 b) can beabstracted recursively within more abstract partitioned subnetworks(FIG. 6 c) and then a single subnetwork (FIG. 6 d). FIG. 6 e illustratesthe transport entities that model the carrying of traffic on the networkand FIG. 6 f shows the concept of network layering as used by thetopology model;

FIGS. 7A-7C show an example of a topology model for a network fragment,where FIG. 7A is the topology model at the optical path level, FIG. 7Bshows the topology model at the optical multiplex section level, andFIG. 7C shows the layered model for the same network;

FIGS. 8A and 8B show the topological model objects, where FIG. 8A is anexample of a network represented by the topology components, and FIG. 8Bshows the topology model objects for the example of FIG. 8A

FIGS. 9A and 9B show the associations between the NE information modeland topology information model for providing the system managementinformation model. FIG. 9A illustrates the possible association betweenthe NE information model and topology information model and FIG. 9Bshows the association for the example of FIG. 8A;

FIG. 10 shows the NMS-UNI information model;

FIGS. 11A-11D show another example of a network model for illustratingcall modeling. FIG. 11A shows a four node physical network, FIGS. 11Band 11C illustrate the topology and NE information models respectivelyfor the network of FIG. 11A, and FIG. 11D shows the association betweenthe topology and NE information models;

FIGS. 12A-12C illustrate how a call is modeled on network model of FIG.11D, where FIG. 12A shows the reserved 0:2 call, FIG. 12B shows theactivated 0:2 cal and FIG. 12C illustrates the SNC and cross-connectionsfor the 0:2 call; and

FIGS. 13A and 13B show how a failed trail is restored for the example ofthe 0:2 call in FIG. 12A, FIG. 13A shows the model for the protectiontrail, and FIG. 13B shows the model for the reverted 0:2 call.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 illustrates a fragment of an agile optical network 100 fordefining some terms used in this specification.

“Agile optical network” (also referred to as “photonic network”, “alloptical network”, “automatically switched optical network ASON”, or“wavelength switched network”) refers to a WDM network, which allows totransparently convey user traffic of various formats on end-to-end(rather than point-to-point) connections. The term ‘connection’ refershere to an end-to-end logical route, which can be set-up along aplurality of physical trails (routes, paths). For example, an A-Zconnection transporting traffic between node A and node Z, can beestablished along an end-to-end trail A-B-C-D-E-Z, or along analternative end-to-end trail A-B-F-D-E-Z.

Connection are established in real-time (rather than beingpreprovisioned) in agile network 100, the user traffic beingautomatically switched at all or some intermediate nodes in opticalformat.

The term “wavelength switching node WXC”, or “flexibility point” or“switching node” refers to a node A, B, C, D, E, F or Z of network 100,which is equipped with a switch 2 for switching the traffic from aninput fiber to an output fiber, and where traffic may also be added ordropped.

The nodes of network 100 are connected over a line system, whichincludes the fiber 9 and the optical amplifiers 8, 8′ that condition theWDM traffic for long and ultra long haul transmission.

FIG. 1 also shows an OADM node 3. Such a node enables add, drop andoptical passthrough. The difference from a switching node is that theOADM does not switch traffic from a line to another; it is connectedover a single line.

A block diagram for a node that enables add, drop or add/drop (i.e. OADMnodes 3 and some switching nodes 2) is shown in the insert for node F.An electro-optics system 6 performs on/off ramp of client signalsonto/from the optical network and interfaces with the network over anaccess multiplexing and switching systems 4. Electro-optics system 6includes transponders 5 (a long reach LR Tx-Rx pair and a short reach SRTx-Rx pair), which are the interface between the network and the user'sequipment. Regenerators 7 (a LR Tx-Rx pair) are also part of theelectro-optics system 6; they provide OEO-based wavelength regenerationand conversion in the network core. In network 100, regenerators 7 areprovided only at switching nodes 2 and OADM nodes 3. They are switchedin a route only when necessary for signal conditioning (at OADM and WXCnodes) and/or for wavelength conversion (at WXC nodes).

Access multiplexing/demultiplexing system 4 provides distribution ofindividual wavelengths from the line 9 to the optical receivers andprovides aggregation of individual wavelengths from, the opticaltransmitters onto the line system.

The term ‘optical path’ refers to the portion of a connection between atransmitter and the next receiver; the user traffic is carried along theoptical path on an optical channel automatically allocated to theoptical path. The term ‘channel’ is used to define a carrier signal of acertain wavelength modulated with an information signal.

An end-to-end trail assigned to a connection may have one or moresuccessive ‘optical paths’, using regenerators at the ends of theoptical paths for wavelength conversion or signal conditioning as/ifneeded. In the example of FIG. 1, the end-to-end trail A-B-C-D-E-Z hastwo successive optical paths. A first path OP1 originates at node A,where the transmitter of transponder 5 modulates the user traffic over acertain channel of wavelength λi. The path OP1 passes through node B andC in optical format and ends at node D, where the receiver ofregenerator 7 recovers the user traffic carried by λi. A second opticalpath OP2 connects nodes D and Z, using another channel of a wavelengthλj, or reusing λi. Regenerator 7 is used at node D for conditioning theuser traffic, or for changing the carrier wavelength.

The term ‘section’ or ‘span’ refers to the portion of the network 100between two optical amplifier huts. For example, span S2 includes thefiber 9 between the output of amplifier 8 and input of amplifier 8′ andthe equipment making-up the optical amplifier 8′. Link L has threespans, denoted with S1, S2 and S3. The term ‘link’ is used for theportion of the network between two successive flexibility sites, such aslink L shown between nodes B and C. This term should not be confusedwith the link object used in the network model.

Network Management

Network 100 is managed by an intelligent network operating system NOS 1,shown in FIG. 2. NOS 1 allows, among other functions, end-to-endconnection provisioning without manual intervention, selectiveregeneration for the passthrough channels in need of conditioning, fulltransmitter wavelength agility and assignment, photonic layer UNI (usernetwork interface). It also allows fault monitoring, photonic layernetwork management, and contributes to automated commissioning,integrated planning and engineering applications.

The NOS 1 of photonic network 100 maintains a real-time view of thenetwork resources, their actual and estimated performance and theirconnectivity. The NOS represents this information using a distributedobject-oriented approach. This is enabled mainly by:

1. Provision of an additional processing platform at the physical layerand the associated signaling and control, to allow monitoring andcontrol at optical modules level, shelf level and NE level. Thisapproach broadens the definition of the managed objects to include themanaged objects of the embedded platform layer (card-packs and shelves).

2. Provision of an optical topology channel between all modules ofnetwork 100 and extension of data communication and signaling at theembedded platform layer. This enables a hierarchical, down-up reportingof network configuration.

3. Provision of monitoring points throughout the network for collectingreal-time optical layer performance data. This data is used in opticalcontrol loops, which set and maintain the parameters of the opticaldevices within the operational ranges. In this way, the network isunconditionally stable in the presence of channel add, channel removeand other churn.

4. Provision of a signaling and control network 55 (see FIG. 10). Thisinternal network supports the management and control functions byenabling communication of control and monitoring data between allinterested entities in the network.

These enablers are described in the above-identified co-pending patentapplications 10/159,676 and 09/876,391.

The management and control functions of the NOS 1 have a layeredarchitecture that build on a modular hardware structure; the distributeddata architecture also follows-up this hierarchical arrangement.

The computing platforms include an embedded processing platform EP 15which operates at the module and shelf layer, a network services controlplatform 17, which operates at the link and connection layer, and anetwork management platform NMP 11, which operates at the network layer.

Provision of the embedded layer 15 enables extending the intelligenceinto the physical layer of network 100, to allow new networkfunctionality such as scalability and automatic routing and switching.

The embedded processing platform 15 has two distinct sub-layers ofprocessing, namely a circuit-pack (CP) embedded layer and a shelfembedded layer. More precisely, most card packs use a standard cardequipped with an embedded controller 20 and optical connectors toreceive the specific optical modules that provide the respectivefunctionality. The shelf embedded platform includes the shelf processors30 provided on all the shelves that make-up optical network 100. Allshelves of network 100 use a standard backplane and are equipped with astandard shelf processor SP card and a plurality of specific card-packsto provide the respective shelf functionality.

A SP 30 manages and controls the ECs in the respective embedded domain(a shelf of equipment) over a shelf network, and provides an interfacewith the NSC platform 17. Each shelf processor SP 30 distributesaddresses to the optical modules in the domain under its control, andcollects topology and performance data based on these addresses andadjacency information. As the card-packs may be inserted in any cardslot of a shelf, each SP 30 determines if the card-packs in therespective embedded domain form a legal entity based on templates, andalarms illegal configurations.

The NSC platform 17 comprises a network services controller (NSC) 40 foreach switching node, such as nodes A, C, Z in FIG. 1, to provide network100 with control, signaling and routing capabilities.

A NSC 40 manages and controls the shelf units in a negotiated span ofcontrol (SOC). The signaling and control network allow communicationbetween the NSC and the managed objects in its SOC. A NSC 40 isresponsible with distributing addresses to all managed elements in theSOC, determines if the shelf units form a legal entity and alarmsillegal configurations.

The primary functions of the NSC are routing and switching control shownat 12, connection control shown at 14 and OAM management shown at 49.The R&S control 12 is equipped with a routing and switching mechanism,which finds the best trail for a connection according to various classesof service. Details on operation of R&S module are provided in the aboveidentified co-pending U.S. patent application Docket 1021US.

Performance of each connection is also monitored and controlled from NSCplatform, as shown by the network connection controller block 14. NCC 14uses measured data collected in various points of the network, andnetwork-wide performance targets to maintain the performance of aconnection at a desired level. Details on operation of this control areprovided in the above-identified co-pending U.S. patent applicationDocket 1010US2.

The OAM (operation, administration and maintenance) applications aredistributed between the NSCs computing platform and the EC and SPcontrollers. It is illustrated in FIG. 2 as a function of the NSC onlyfor simplicity. Thus, provisioning of managed elements is an SP and NSCactivity. The associated CPs specify which modules they contain andstimulate the appropriate object creation at the SP and thedetermination of the shelf type. Once an appropriate number ofinterconnected shelves are discovered, as guided by ME (managed element)templates, a ME is created. For amplifiers 8 and OADMs 3 this functionis carried out by the SP 30, but for the more complex switched nodes 2,the NSC 40 manages the ME creation. Performance monitoring is performedat both NSC and SP levels.

Each NSC 40 constructs, from queried information, SOC-relatedinformation for the embedded elements under its control. The physical,logical and topological data defining all network entities are stored asmanaged objects in a persistent storage area. This is genericallyreferred as the MIB (management information base) 10, which is in factdistributed throughout the network (see FIG. 3).

A distributed topology server DTS 90 assembles a complete view of thenetwork at each NSC. The network view is maintained in aresource-oriented DTS database 91. DTS 90 t also provides applicationmanagement through interface 95, which enable various networkapplication to access the database 91. The optical path resources, whichare necessary for the R&S mechanism to enable end-to-end connectionconstruction, are the transponders, regenerators, wavelengthtranslators, wavelengths, tunable filters/VOA pairs.

The DTS MIB interface 93 is responsible for the creation and deletion ofall topological components in the DTS database 91. Interface 93 isinformed when all the managed elements in a link have been created, atwhich point it creates a new link in the DTS database 91. Othertopological components such as transponders and regenerators are createdimmediately upon notification of their creation in the NSC MIB.

The interface 94 is responsible with flooding local DTS information toall other DTS's in the network. It uses for example an OSPF (opticalshorter path first) protocol.

For example, R&S control 12 shares this information with neighboringNSC's to build a complete network view for enabling automatic routingand switching and dynamic set-up and removal of connections. Only thelocal SOC view is stored at this level for access by the managementplatform 11. The management platform 11 constructs a full networktopology by assessing all NSCs and aggregating the SOC information intoa distributed topology system.

At the highest level, the management platform 11 provides the computeresources required to perform network management. Typically, itinteracts with the NSC platform 17 and a planning platform 13 and aplanning platform 13. The management platform comprises a plurality ofapplications, such as performance, fault, configuration and securitymanagement applications. Also the common applications, such as systemmanagement and software distribution, may reside on platform 11. Thenetwork clients use unique address ranges distributed manually to allNSC's. Alternatively, platform 11 may distribute and maintain theseaddresses inaccessible to the network client.

Planning platform 13 hosts the planning and engineering, which enableoff-line planning and engineering of the network. The constructednetwork can be shared with the management platform 11 e.g. foroptimizing network evolution plans based on most up-to-date networkdata. Platform 13 also allows the provider to specify the networkoperating targets such as dispersion, power per channel, channel usage,etc.

A craft platform 19 enables simple nodal management and control of anyplatform over interfaces to the NSC platform 17 and embedded platform15. It provides the ability to query and set various nodal parameters,to remotely access and launch management platform applications, etc.

The decision of which software functions reside on which platforms isdetermined by a number of factors, including response-time requirement,availability requirement, reaction-time requirement, and scalabilityrequirement. A software function may need to reside on more than oneplatform.

Network Information Model

The following terms are used for the description of the networkinformation model,

The term “network element NE” designates a physical piece of equipmentthat provides a logical communication function. That is, from a physicalpoint of view, a NE comprises one or more shelves; the logical meaningassociated with that collection of shelves defines it as a networkelement. Examples of NEs are the optical amplifiers 8 (pre, post andline), the switch 2 and the OADM 3.

A “managed object MO” is a data structure, which describes the functionsand status of a network entity. The managed objects could be bothphysical MOs (e.g. a shelf, a circuit pack, software, etc) and logicalMOs (a connection termination point, a cross-connection).

A managed object has certain attributes and performs certain functions.For example, a cross-connect performs connections set-up or connectionrelease and has attributes such as active cross-connections, faultstate, operational state.

A “topology object” is a data structure that describes a connection or apotential connection across the network.

In an object-oriented approach, objects with the same data structure(attributes) and same function (operation) are grouped into a “class”.

A “managed element ME” is a managed object that represents a networkelement.

The term “network management system NMS” refers to the manager of anetwork which allows the user to interface with the NOS 1. The NMS andNOS communicate using the information stored in the managed objects.

The term “mastered” means that the respective master entity isresponsible for maintaining the definitive state of the object, whichimplies ensuring that the object can be restored under any circumstance.

This invention defines a network model (or core network model, ornetwork information model) that is common to all applications, and showshow the information is maintained and used in the network. The corenetwork model is divided into two models, a network element NEinformation model and a topology information model that are largelyindependent form each other. These models are however associated witheach other; namely the topology model references objects of the NE modelas seen later. Use of a network information model enables extensions tomeet the needs of specific applications. The models use a universalobject description language; the NMS, NSC and embedded groups allgenerate their interface and code from this common language. Extensionsare grouped into packages to simplify their inclusions and exclusionsfrom applications. Applications are able to derive or add their ownextensions including new derived classes or attributes.

Managing the topology information independently from the information onthe network elements that form the network, allows each model to evolveindependently, a model to exist without the others and maps well to theseparation between the network management layer NML and elementmanagement layer EML concept in the telecommunication management networkTMN protocol.

FIG. 3 shows the residence of various MOs in the NOS shown in FIG. 2,and how they are mastered. It shows a NSC 40 and the NEs in its SOC,namely a switch shelf 30-1 and two amplifier shelves 30-2 and 30-2, eachequipped with a respective shelf processor 30. It is to be understoodthat this is an example, a NSC 40 may control a larger number of opticalamplifiers, the NEs generally occupy more than one shelf, and also anNSC may control more switches at the same site.

The objects shown in FIG. 3 are:

Network objects 32 (shown in white), which in this case is an objectrepresenting network 100.

Managed elements 33 (shown in black). Examples of MEs are a switch, anOADM, the line amplifiers in the span of control of a respective NSC 40,etc.

Equipment objects 34 (shown in horizontal stripes). In the case of aline amplifier, these could be the two EDFA amplification stages, theRaman stage, the DCM module and the dynamic gain equalizers (DGE).

Termination point objects 35 (shown in vertical stripes). A terminationpoint can be for example the termination of a channel (transmitter,receiver). In the case of a line amplifier, such an object representstermination of the optical line; while the WDM signal output from theline amplifier has the same channels as the WDM signal input to the lineamplifier, it has different parameters (gain, distortion, tilt, OSNR).

OAM (operation, maintenance and administration) objects 36, shown ingray. These are logical MOs, including the operational parameters of therespective equipment objects.

Topology objects 37 (shown in dark gray). These are for example objectsmanaged by the routing and switching mechanism at the respective NSC.

System objects 38 (shown in light gray) represent the processingplatforms.

Objects that are shown by circles are mastered at the level where theyare illustrated, while the objects that are not mastered at that levelare represented by squares. For example, in the case of a switch NE, theSP aggregates the equipment and the termination objects only; the OAMand topology objects are mastered by the NSC.

At the embedded level 15, a shelf processor 30 is the master of allequipment and termination objects local to that shelf, and also for theOAM objects in line or post/preamplifiers. A SP is also the master forall objects subtended by these objects, namely the respective slots,optical modules, etc. Each SP provides persistent storage for the MOs itmasters, shown at 103.

The network services controller NSC 40 manages all network elementswithin its SOC, such as the optical amplifiers 8 (includes line, pre andpost amplifiers), switches 2, and OADMs 3. At this level, a managedelement is in general a network element. A managed element complex MECmay also be supported at this level (a MEC is for example a switch 2,the drop side of the access system and the OE converting side of theelectro-optics system). The NSC is the master of the “local” OAM objects36, such as software distribution packages, and topology objects 37. Italso provides persistent storage as shown at 102 for the objects itmasters.

The management platform is the master for the network object 32 and itis responsible for all common functions such as the functions that crossplatforms, like security, data and system management, and also formanaging all the NSCs. The management platform logically groups thenetwork elements into sub-networks based on a customer's desired networkpartitioning. This platform is also the master of the “local” OAMobjects 36 as software distribution packages. It provides persistentstorage for the objects it masters; the remaining objects are a “mirror”of the actual network state.

To platform 11 all MOs within an NSC's span of control (SOC) are locatedin the MIB of the respective NSC 40. The fact that the MIB is actuallydistributed between the NSC and several shelf processors is hidden fromthe client.

All MOs in the network information model are hierarchically named, in arooted hierarchy according to some basic rules. Thus, an object can onlyexist if its “parent” exists, and an object can have only one parent. A“local distinguished naming scheme” is used, where each domain has itsown relative root object from which all objects are named. The NMSdomain has a root object 31 for the entire naming tree. Objects in themanagement platform domain carry a full distinguished name (DN). Objectsin the NSC domain carry a local distinguished name (LDN) relative to thenetwork, and the objects in the SP domain carry a LDN relative to thenode.

Distinguished names DN are an ordered list of so called “tuples”(ClassID, InstanceID). For example, a circuit pack in slot 5 of shelf 3in an amplifier named 12345 would have a distinguished name in the NSCof: {(ME,12345)→(EquipmentHolder,3)→(EquipmentHolder,5)→(CircuitPack,1)}Since each class also has an associated ID, the actual DN looks like:{(1,123456)→(3,3)→(3,5)→(4,1)}

1. Network Element Information Model

The primary function of the NE information model is to model the NEsbased on the managed objects (MO) they contain, and specifically not tomodel the network topology in which that NE participates; networktopology is modeled separately.

The NE information model is based in general on the M.3100 ITU-Tstandard, Generic Network Information Model, which defines the ME(managed element) physical and logical components. G.875 Standarddefines optical-specific extensions to M.3100.

In M.3100 style interfaces the NMS creates and names each ME.Auto-creation of all of the MOs is one aspect of the invention, and itdoes impact on the M.3100 model. Firstly, it saves a significant amountof manual data entry and secondly, it avoids many human errors. The MO'snames, which are auto-generated when the object is created, may not bein a form that is optimal for the network provider. For example, networkproviders typically name their network elements in a meaningful way thatcannot be auto-generated. To resolve this issue, the NE interfacesupports a “UserLabel” attribute that the service provider can assignfor human interpretation, for example on alarms and GUI (graphical userinterface) displays.

The NE information model is based on the physical and logical MOs thatthe respective NE contains and their inter-relation.

FIG. 4A shows the general NE information model used in network 100,illustrating the differences from the M.3100 standard in gray. The modelcomprises equipment objects 34 (there could be n such objects),termination point objects 35, and fabric objects 25. An equipment objectsubtends software objects 41, equipment holder objects 42 and circuitpack objects 43. It is to be noted that n shown on the arrows betweenthe managed objects may have a different value for each object.

In this model, a port class 44 was added to model the inter and intrashelf adjacency of cards within a managed element (the physical cablingbetween the cards and between shelves), as seen later in connection withFIG. 5B.

A termination point object 35 could be a tail termination points TTP 45or connection termination points CTP 46, depending on the currentrouting map.

The trail termination points TTP 45 are implemented for the optical path(OP1, OP2 in FIG. 1); unlike traditional DWDM networks, an optical path(channel) is not terminated (OEO converted) at the next node. There is aTTP 45 for each channel on a link, as shown by letter n.

Because of its associations with other objects, a connection terminationpoint (CTP) 46 is an important MO in the NE interface model. The CTP iswhere the “logical” is mapped to the “physical” via a “supported by”relationship with the circuit pack 43 and it is also where the topologyinformation model (see next) maps to the NE interface model via arelationship attribute with a topology object 37. The CTP 46 can becross-connected (i.e. switched) with another CTP using thecross-connection object 47.

The objects subtended by the fabric 25 are the cross-connection object47 and the topology pool (TpPool) 48. The fabric object 25 is thecontainer for all cross-connection objects 47. The TpPool objectsubtends a regenerator pool class 21 and an access pool class 22, whichare extensions to the standard. As discussed in connection with FIG. 1,network 100 is provided with a number of regenerators 7 and therespective access equipment 4, which are dynamically allocated toconnections according to the current connectivity map of the network,and to the performance of individual connections.

The functional MOs of the NE information model are similar to the MOs inthe standard, which defines an alarm management schedule class, a logclass, an alarm severity assignment class and an alarm summary class. Inaddition to these MOs, the functional MOs also include according to theinvention a performance record class and a security record classcontained in the log class.

Each managed object maintains a list with the classes it contains,objects it affects, supports and inherits from.

FIG. 4B shows an example of a NE information model for a managed objectcomplex (MEC), for exemplifying the relationship between various classesin the NE information model. In this example, MEC 23 has two managedobjects 33-1 and 33-2, each having the respective physical classes,shown in white, and logical classes, shown in gray. For example thephysical classes shown are bays, shelves and slots equipment holders 27,28 and respectively 29, circuit pack 43, optical modules 39. The logicalclasses shown are alarm summary 24, log 26, fabric 25, CTPs 46, software41. In this representation the equipment holder 42 of FIG. 4A is shownin more details to represent hierarchically the bays, shelves and slots.In addition, FIG. 4B also shows the city container 16 and buildingcontainer 18 which “contain” the equipment holder bay 27 for bothmanaged elements of MEC 23. The equipment holders are also shown on theleft side of the drawing. The equipment class 34 “inherits from” allequipment holders, as shown by the dotted lines, and the container 18“inherits from” the equipment 34.

The thin lines between the classes illustrate hierarchically the namingentity. For example, the ME 33-1 “names” the CTPs 46, the fabric 25, thelog 26 and the alarm summary 24. The thick lines show the “managed by”relationship. Thus, MEC 23 “manages” ME 33-1 and 33-2, and each ME inturn manages an equipment holder (shelf or slot). Network object 32manages MEC 23.

FIG. 5A illustrates the relationship between the connection terminationpoint objects 46 and the circuit pack objects 43. A circuit-pack pointsto a list of objects “affected by” it. Thus, circuit pack 43-1 maintainsa list with CTP 46-1 and CTP 46-2, and the “affected by” list maintainedby circuit-pack 43-2 shows CTP 46-3, 46-4 and 46-5. A CTP points to thecircuit pack that it is “supported by”. For example, CTP 46-3 points tocircuit pack 43-2. The CTPs on the same CP are also affected by otherCTPs on the same card pack. Thus, CTP 46-3 is “affected by” CTP 46-5 andCTP 46-4. The “supported by” relationship is shown in dashed lines, andthe “affected by” relationship is shown in dotted lines. The thick lineshows that the ME 33 manages equipment holder 28.

FIG. 5B shows circuit pack adjacency. Circuit pack adjacency isaccomplished by trace information 80 that flows in one direction fromport to port, between a CTP source 44So and a CTP destination 44Si. Inthis example, as shown on the left side of the drawing, the fiber andthe trace channel (which travels on the same fiber with the WDM signalor on a tandem fiber) enter the shelf at circuit pack 43-3 in slot 3 andexit at circuit pack 43-4 in slot 4, after passing through circuit pack43-5 in slot 5. The CTP for the optical trace channel can locate an“associated port” by first locating the CP via the “supported by” list,and then traversing the list of “affected objects”. The relationshipbetween the ports 44 and 44′ on each card is “upstream-downstream” sincethe trace flow is unidirectional.

FIG. 5C is an example of modeling regenerator pools and access pools fora 3×3 switching node. As shown in FIG. 4A, the fabric object 25“contains” n TpPool objects 48, which, according to the invention,“inherits from” access pool class 22 or/and regenerator pool class 21.

A 3×3 switching node has three input and three output lines, each lineprovided with a respective add/drop structure 4, shown by access pools22-1, 22-2 and 22-3. As an optical channel originates and terminates ona transponder connected to an access route, these connection terminationpoints are shown at 46-1, 46-2 and 46-3 respectively. The black rhomb atthe fabric object indicates that the fabric contains and references therespective objects.

The regenerator pools 21-1, 21-2 and 21-3 illustrate the pools that areconnected between input and output lines 1-3, 1-2 and 2-3 respectively.In this example, there are four regenerators, regenerators 7-1 and 7-2connected between lines 1-3 for both directions, and regenerators 7-3and 7-4 connected between lines 2-3 for both directions. Theregenerators have two CTPs 46, since each terminates an optical path andoriginates a new optical path; however the trail is not terminates andit continues on the same or another channel.

2. Topology Information Model

The topology information model is based on the M.3100 Amendment 1standard, which itself is based on G.805 ITU-T standard. The primaryfunction of this model is to model the topology of the network andspecifically not to model the network elements that implement thetopology. As indicated above, the topology information model doesmaintain associations with the NE model to facilitate mapping betweenthe two views.

The definition of the terms used for the network topology model isprovided in connection with FIGS. 6 a-6 f. These figures show theclasses of objects used for this model (see 37 on FIG. 2). Namely thetopological components are shown in FIGS. 6 a-6 d, and the transportentities are shown in FIGS. 6 e and 6 f.

The topological components express the static interconnections betweennetwork components. FIG. 6 a shows the topological components as definedby the standard:

A layer network 50.

An access group, such as 51A and 51B. A layer network 50 describes acomplete set of like access groups 51A, 51B, which may be associated forthe purpose of transferring information. Access groups describeco-located trail termination functions connected to the same link orsubnetwork.

A subnetwork 52A, 52B, which describes the potential for subnetworkconnections.

A link 53A, 53, 53B, which describes the fixed relationship betweensubnetworks 52 or access groups 51 and subnetworks 52 and may containplurality of link connections.

A link end 54, which describes the capacity of the ends of the link.

The subnetworks 52 can be recursively partitioned into interconnectedsubnetworks and links 53. This nesting ability means that the detailsabout parts of the network can be hidden or abstracted.

FIGS. 6 b to 6 d show how a detailed network can be abstractedrecursively within more abstract partitioned subnetworks untilultimately the entire layer network is represented by a singlesubnetwork. The example of FIG. 6 b shows a layer network encompassingsubnetworks 52-1 to 52-5 connected by links 53. Access groups 51C, 51Dand 51E represent the trail termination functions connected to links53C, 53D and 53E, respectively. FIG. 6 c shows how subnetworks 52-1 and52-3 are abstracted into a partitioned subnetwork 52C and subnetworks52-2 and 524 are abstracted into a partitioned subnetwork 52D. In FIG. 6d, subnetworks 52C, 52C and 52-5 are abstracted into a singlepartitioned subnetwork 52, which includes all the links between thesubnetworks 52-1 to 52-2.

The transport entities include:

A trail 60, which is responsible for modeling the client layer trafficbetween the source point A and the destination point Z.

A subnetwork connection, as shown at 62BC and 62 DE, which isresponsible for modeling the traffic across a subnetwork; and

A link connection, as shown at 63A, 63, and 63Z, which is responsiblefor modeling the traffic across a link.

The extension to the standard refers to the network termination points65. Namely, the standard specifies that an ‘adaptation function’ and a‘termination function’ terminate an optical path. These functions arereplaced in the topology information model according to the inventionwith the network termination points, with a view to enable a universalcommon model across the processing platforms. The function of thenetwork termination points in the topology information model is to bindtogether the transport entities to form the respective end-to-end trail.

In the topology information model, a trail termination point TTP 65terminate an end-to-end trail 60 (source A to destination Z), and iscontained in an access group 51, while a connection termination pointCTP 66 terminates a link connection 63 and is contained in a link-end54.

The telecommunications networks tend to use many different technologiesto actually carry traffic across an end-to-end connection. That is, theactual transport network can be decomposed into a number of independentlayer networks with a client/server relationship between adjacent layernetworks.

FIG. 6 f shows the client/server relationship between layer networks 70and 71 used in the context of the topology model according to theinvention. In server layer 71, the CTPs 66B, 66C, and 66D, 66E bind thelink connections 63 to the subnetwork connections 62BC and respectively62DE, and the TTPs 65 bind connection termination points 66′, 66″ in theclient layer network 70 to the trail 60 in the server layer network 71.In client layer 70, the CTP 66′ and 66″ bind the link connection 63′.Link connection 63′ in client layer network 70 is implemented by a trail60 in the server layer network 71. This can be realized by associatingCTP 66′ in the client layer 70, with a TTP 65 in the server layer 71.

A basic topology information model implements the first three layers ofan optical network, namely the Optical Channel (Och) layer network, theOptical Multiplex Section (OMS) layer network, and Optical TransmissionSection (OTS) layer network. More complex models can go at the lowerlevels, to include the Physical Media (Phy) layer network and also, anadditional layer (not defined by the standard), the Conduit layernetwork.

The Och layer network provides end-to-end networking of optical channelsfor transparently conveying client information of varying formats. TheOMS layer network provides functionality for networking of amulti-wavelength optical signal. The capabilities of this layer networkinclude ensuring integrity of the multi-wavelength OMS adaptedinformation, and enabling section level operations and managementfunctions, such as multiplex section survivability. The OTS layernetwork provides functionality for transmission of optical signals onoptical media of various types. The capabilities of this layer networkinclude ensuring integrity of the optical transmission section adaptedinformation and enabling section level operations and managementfunctions (such as transmission section survivability).

The Phy layer network models the cable in which the fibres arecontained, and the Conduit layer network models the physical conduit inwhich a cable runs.

This basic topology information model assumes that an OTS link is in aone-to-one relationship with a Phy link, which is in a one-to-onerelationship with a conduit link. In this case, additional attributesare kept on an OTS Link to characterize information that would normallybelong to a lower layer. It is understood that this is not a completelyaccurate model but it does allow the system to take advantage of many ofthe benefits normally provided by the lower layers. For example, aConduit Id can be maintained at the OTS Link to capture a simplifiedview of the conduit in which a fiber it contained.

FIG. 7A shows an example of a trail at the optical channel layer (Phy)for illustrating how a topology information model is built, usingtopological components, transport entities and termination points. Thefragment of network of interest for this example includes twobidirectional lines 9-1 and 9-2 connecting nodes A, D and G.Bidirectional optical amplifiers 8B and 8E are provided between nodes online 9-1, and bidirectional optical amplifiers 8C and 8F, on line 9-2.FIG. 7A also shows a trail 60 that originates at node A, is switched byintermediate node D from a line 9-1 to line 9-2, and terminates at nodeG. The traffic on this connection is conditioned by the respectiveoptical amplifiers 8B and 8F. Only the add side and the respectivetransmitter 5 are shown at node A, and the drop side and receiver 5′ areshown at node G.

The topological objects at the optical channel layer are subnetworks52A, 52D and 52G for each respective switch, connected respectively bylinks 53AD and 53DG. Links 53A and 53G connect the subnetworks 52A and52G to the respective access group.

The transport entities are the subnetwork connections 62A, 62D and 52G,and the link connections 63AD and 63DG. The optical amplifiers areabstracted in the links at this level.

The network trail termination points in this example are 65A and 65G atthe ends of trail 60. The network connection termination points aredenoted as in FIG. 6 e with 66, and they terminate the link connectionsand are contained in the respective link ends.

FIG. 7B shows the model of the same network fragment as in FIG. 7A atthe optical multiplex section level. At this level, there are two OMStrails 60′ and 60″, and the links 63AD and 63DG are now shown moredetail. Namely, the optical amplifiers 8B and 8F are represented bytopological components subnetworks 52B and 52F respectively, and theirtransport entities subnetwork connections 62B and 62F. The trailtermination points for OMS trail 60′ are 65AB and 65BD and for OMS 60″are 65DF and 65FG at this level. The connection termination points forthe link connection are not illustrated at this level, but they are asbefore at the ends of each link 53AB, 53BD, 53DF, and 53FG.

FIG. 7C shows the layered model that binds the optical channel layernetwork 70 to the OMS layer network 71 in a client-server relationship,where network 70 is the client layer and network 71 is the server layer.Now, the link connections 63AD and 63DG in the client network 70 areimplemented by a respective OMS trail 60′, 60″ in the server layer 71.Thus, within the server layer 71, the link connections 63AB and 63BDbind the subnetwork connection 62B to trail termination points 65AB and65BD respectively, and link connections 63DF and 63FG bind thesubnetwork connection 62F to trail termination points 65DF and 65FGrespectively. The OMS trail termination points 65AB and 65BD bind therespective optical channel connection termination points 66AB and 66BDin the client layer network 71 to OMS trail 60′. Similarly, the trailtermination points 65DE and 65FG bind the respective connectiontermination points 66DF and 66FG in the client layer network 71 to OMStrail 60′.

It is to be noted that the topological components are created only afternetwork commissioning. The link objects contain a list of connectiontermination points at each end, which bind to subnetwork connectionsonly when a path is created. The access groups contain trail terminationpoints that will terminate an end-to-end trail when required.

The system management actions cause topology objects of the opticalchannel layer, specifically the transport entities, to be created,deleted and updated. For example, as connections are established theappropriate trail 60, CTP 66, TTP 65, subnetwork connections 62, andlink connections 63 are created in the optical channel layer. This isthe only mechanism in the network that creates these topology objects.

FIG. 8A is an example showing the topological components for a trail ACestablished over a network comprising nodes A, B, C and D. Forsimplification, the subnetworks illustrating the nodes are designated bySN-A, SN-B, SN-C and SN-D, the links between the subnetworks aredesignated with link1 to link6. The access groups, designated with AG1and AG2 are shown at nodes A and C respectively, since the connectionoriginates at node A and terminates at node C.

FIG. 8B illustrates the topology model for the network fragment shown inFIG. 8A. Transient subnetwork connections SNC are created on thesubnetworks SN-A to SN-D. These SNCs are grouped together in trails todefine an end-to-end connection. The CTP bind the subnetwork connectionsto the links. Trails are referenced by a client link to gain access tothe server layer that implements it. A link may point to one or moretrails.

Although the above NE and topology models are specified separately,there are some inter-dependencies between them. Thus, there is a one-wayassociation between the Network CTP class of the topology model and theCTP class of the NE information model. FIG. 9A show the only possibleassociations between the NE information model and topology informationmodel. This association is used to relate the topology view to thenetwork element implementation view. In the network model, a topologynetwork CTP object 66 can be associated with an NE CTP object 46. Also,a topology subnetwork 53 or access group object 51 can be associatedwith a NE managed element 33. These are one-way associations. A topologysubnetwork connection object 62 can be associated with a NEcross-connection object 47. This is a 2-way association. In this way,the NE objects maintain the network implementation details (e.g.wavelength, power, BER, alarms). Topology objects maintain genericconnectivity information (e.g. trail ID, CallId, Reservation Status).Only the cross-connection object can navigate between the two models.

FIG. 9B illustrates the association between the models for the networkfragment of FIG. 8A. The objects of the NE information model are shownwith horizontal stripes, and the dotted lines indicate the associationbetween the models. Also, for simplicity the objects the NE informationmodel are called “managed objects”, and the objects the topologyinformation model are called “topology objects”

3. NMS-UNI Information Model

FIG. 10 shows the network model intra-network communications andcommunication between the service provided domain and user domains. Thephysical network 100 includes in this example three nodes A, B and C,each node being monitored and controlled at the link and connectionlayer by a respective NSC 40A, 40B and 40C of network services controlplatform 17 (see also FIG. 2). Internal communication is performed overa signaling network 55, using UNI interfaces, namely a NMS-UNI interface56 enables communication between the NMS and the NSC platform 17 and aUNI-N 57 enables communication between the NSCs 40.

Communication between the user domains and the network domain isperformed over a UNI-Signaling interface 58 and a UNI Transportinterface 59. The behaviors of the NMS_UNI interface 56 is similar tothe user domain UNI-Signaling interface 58, but under the control of theservice provider instead of end-user.

Signaling over the UNI is used to invoke services (e.g. connections)that the optical network offers to clients. The properties of aconnection are defined by the attributes specified during connectionestablishment.

UNI Signaling interface 58 is used to invoke the following actions:

Connection creation. This action allows a connection with the specifiedattributes to be created between a pair of client points of attachmentto the optical network. Connection creation may be subject to networkdefined policies (i.e. user group connectivity restrictions) andsecurity procedures.

Connection deletion. This action allows an existing connection to bedeleted and the resources allocated to that connection freed.

Connection status enquiry. This action allows the status of a certainparameters of the connection to be queried.

The NMS-UNI interface 56 adheres to and extends the OIF specification.Specifically, the extensions include adopting the CMISE-like frameworkprotocol, so that a single protocol is used for all NMS to NSCinterfaces. Another extension refers to the addition of a reserve-onlycapability to enable a user to select a single path from a set ofpossible reserved paths.

The NMS_UNI interface 56 is modeled by a single managed object calledNMS_UNI, which is contained within the switch managed element object.The NMS_UNI generates alarms and maintains operational andadministrative state.

Modeling Optical Calls

The following description provides an example on how a call isestablished using an example of a network 200 shown in FIG. 11A. Network200 has four nodes A-D, where node C is provided with a 3×3 wavelengthswitch. The optical call in this example intends to establish connectionbetween the transmitter of a transponder 5 at node A, to the receiver ofa transponder 5′ at node D.

FIG. 11A also shows two regenerators 7 and 7′ at intermediate node C onebridging links link4 and link5, and the other, link4 and link6.

Network 200 is represented in the MIB 10 (see FIGS. 2 and 3) by thetopology objects shown in FIG. 11B.

In FIG. 11B, subnetworks SN-A to SN-D represent the switchingcapabilitiesy of nodes A to D. Each link object link1-to link7represents fixed connectivity between the wavelength switches, eachpotential channel in a link is associated with a network connectiontermination point at each end of the respective link, as shown by CTP1to CTP14. It is to be noted that the link objects were denoted with thesame reference as the physical links in FIG. 11A for simplification.

The entry/exit points of the network are modeled with a respectiveAccess Group AG1 and AG2, where each access group contains a respectivetrail termination point TTP1, TTP2, which represent the terminationpoint of an end-to-end call in the network. The regenerators 7 and 7′ donot represent anything at the topology level since they contribute notopological information.

It is to be noted that the topological objects shown in FIG. 11B are nottechnology specific, as they are independent of implementation. In otherwords, the topology model does not give any indication that itrepresents optical network 200. No traffic is being carried in thenetwork yet, so the transport objects will be created as/when the callis established.

The NE model for switching node C is shown in FIG. 11C; as indicatedabove, this model expresses the actual equipment that implements node C.All objects are contained within the switch C managed element 33. Theregenerator pools 21 and 21′ contain the one regenerator each in thisexample, namely regenerator 7 and regenerator 7′. Equipment holderobjects 28 and 29 model the shelf and slot respectively, and the circuitpack objects model the cards in the slots.

The optical channel connection termination points CTPs 46 represent thecapability of ME 33 to carry optical channels and represent the state ofa channel on ingress to and egress from the switch. They also contain a“supported by” object list, which map them to the physical circuit packswhich support them. The circuit pack objects 43 contain an “affected”objects list that list the CTPs which they affect. The circuit packobjects model the transmitters 43Tx, 43′Tx and the receivers 43Rx, 43′Rxof regenerators 7 and 7′, and other card-packs, as shown at 43′, 43″ and43TR.

It is to be again emphasized that the NE model in FIG. 11C does not giveany topology information. That is, no information about how MEs areconnected together is represented.

FIG. 11D depicts both the topology and the implementation of thenetwork, as obtained by associating the two models in FIGS. 11B and 11C.FIG. 11 also shows the associations between the models, namely theassociation between network CTP 66 and optical channel CTP 46,subnetwork 52-A and ME 33, and network TTP 65 and optical channel TTP45.

Although CTPs exist in both models, its important to reiterate that thenetwork CTP in the topology model is completely generic while theoptical channel CTP in the ME model is specific to modeling an opticalchannel termination point.

Also, note that in this example two of the network CTPs 66 at the end oflink1 point to the same optical channel CTP 46 of the NE model. This isbecause in this representation the transponders and the switch arecontained in the same ME 33; in this case the topological link object isvirtual. When network 200 supports a remote TR, the link object isphysical and the two network CTPs refer to two optical channel CTPs.

A 0:2 call refers to a class of service that provides a primary trail Pfor carrying the traffic and simultaneously a secondary trail S forprotection/restoration, using a different set of end transceivers. Theprotection function is naturally included in the routing function; aconnection request lights the P and S trails at the same time. Let's saythat a call request is received by network 200, requiring a 0:2 CoS onan A-D connection, with forced regeneration at node C, as shown in theinsert at FIG. 11A. “Forced regeneration” refers to the constraintreceived with the call to perform regeneration at node C.

To establish this call, the NOS sends a ‘connection create’ action tothe R&S control 12 (see FIG. 2). This request specifies the two ends Aand D for both P and S trails, which results in four TTPs 65P and 65′Pfor trail P, and 65S and 65′S for trail S, and the forced regeneratorinclusion node C; as shown in FIG. 12A. R&S control 12 (see FIG. 2) usesthe four TTPs to find the four associated CTPs 66P, 66S, 66′P, 66′S onthe end links link1 and link7 of the requested call. The four CTPs andthe regenerator location are then used as end-points for the R&S control12 to determine the two paths P and S. Once the paths are determined thefollowing steps will occur:

A Call Id is created. Both trails P and S have the same Call Id.

A trail Id is created. Trails P and S have a different Trail Id

All of the associated CTPs are reserved, by setting a ‘UsageState’attribute to ACTIVE and incrementing a ReferenceCount attribute by 1.

The Call Id is stored in all CTPs

Subnetwork connections (SNC) 62 are created for each P and S trail,binding the appropriate CTPs.

The appropriate Trail Id is stored in each SNC 62.

The appropriate Trail Id is stored in each TTP.

Layer 17 reserves the explicit regenerators 7 and 7′ at the switch C NEby issuing a “reserve” action on the appropriate regenerator pool 21,21′ and using the Trail Id as the reservation identification, as shownin dotted lines on the NE model of FIG. 11C.

The Call Id, Trail Id and list of ingress/egress CTPs is returned to theNOS.

The Call is now in a ‘reserved status’ and ready to proceed toActivation. FIG. 12A shows the physical view of the routes (light grayfor P trail and darker gray for S trail) in the ‘reserved status’; bothP and S trails pass through node C because of the forced regeneratorsrestriction, illustrating the newly created subnetwork connections SNC-Ato SNC-C and their state. As indicated above, both trails have the sameCall Id in their CTPs but the SNCs and TTPs have different TrailId foreach path.

The NEs are largely unchanged by reserving the trails, with theexception of switch C NE, where the regenerator pool objects 21 and 21′have an attribute ReservedRegenCount=1 and a ReservationId=TrailId. Itis to be noted that the resources are usually reserved in the topologyinformation model, with the exception of regenerators, which arereserved in the NE information model. Once a subnetwork connection iscreated, but not activated yet, it can reserve a regenerator from theregenerator pool 21, if explicitly requested by the call originator.Reservation can be either a specific regenerator 7, or any regeneratorin the respective pool 21.

Layer 17 then sends two ActivateTrail commands to the respective NCC 14(see FIG. 2). Each command comprises a trail description, which containsinformation about each hop in the connection, including theingress/egress CTPs, the NSCs addresses and the pertinent regeneratorinformation (inclusion, exclusion).

For each ingress/egress CTP in a trail, the NCC 14 (see FIG. 2) sends anActivateCrossConnection request to an optical switch controller (notshown) on the appropriate NSC 40. The request contains the CTPs, theReservationId and regenerator information, if any.

Each switch controller receives the ActivateCrossConnection requestactivates the call as described next and shown by the topological viewin FIG. 12B.

Finds the associated optical channel CTPs 66. For example, the switchcontroller finds CTP 66-1′P and CTP 66-4P for the P trail and CTP 66-1′Sand 66-2S for the S trail.

Checks for an explicit regenerator (here at node C) and uses aRegenReservationId action to allocate the regenerators and update theReservationIdList and ReservedRegenCount at the regenerator pool object;

If a regenerator is required, creates two cross connection objects 47 aand 47 b as shown in FIG. 12C; one between the ingress tandem CTP 46 aand the ingress regenerator CTP 46 a′ and another one between the egressregenerator CTP 46 b′ and the egress tandem CTP 46 b.

If no regenerator is required, it creates a single cross connectionobject between the two associated tandem CTPs 46 a and 46 b.

Links all cross connection objects 47 in the NE model and the SNCs 62together using two-way name references. This is shown for node C in FIG.12C.

Sets the UsageState for the SNC 62, optical channel CTPs, and networkCTPs to BUSY.

Returns a successful ActivateCrossConnectionResponse to the NCC.

Once the NCC 14 receives successful responses from all switchcontrollers, it returns a successful ActivateConnectionResponse to theR&S control 12.

Once both trails have been activated, the R&S control 12 sets theUsageState of the network TTPs to BUSY and returns a successfulConnectionCreateResponse to the NOS. The 0:2 Call is now activated.

FIGS. 13A and 13C show how a failed trail is restored for the example ofthe 0:2 call discussed above. Let's assume now that link4 fails asmarked on FIG. 12A, and trails P must be recovered. The fault managementof NOS will detect a Loss Of Signal LOS error reported by the opticalchannel CTP on link4. The R&S control 12 associates the LOS with theaffected trail, in this case trail P and the call, in this case the 0:2call requesting to connect nodes A and D. The R&S control 12 thendeactivates the failed trail P by sending a DeactivateTrail command tothe NCC 14, which passes this to all subnetwork connections along thistrail.

The NCC 14 also directs all associated switch controllers to delete thecross connection objects associated with the NE model for the networkelements along trail P. Essentially, the failed trail is returned fromthe “Busy” state to the “Reserved” state, shown in FIG. 12A.

The R&S mechanism of R&S control 12 now begins to establish theprotection path by re-sending the end CTPs to the routing engine. Sincethe failed trail P has been completely deactivated, its resources arenow available for reuse by trail S. Only trail S is allowed to reusethese resources. The system can easily enforce this since trails P and Scarry the same Called.

The R&S control 12 is provided with the link4 as a new constraint and anew path is determined. For this example, it is assumed that theexplicit regenerator constraint does not propagate to the redialed path.Should this change, the regenerator constraints could also be providedto the R&S control.

R&S control 12 creates a new TrailId, e.g. TrailId=3, and reserves therequired CTPs as before. The R&S control then stores trail S in aStandbyTrailRef attribute of the original P trail. A ProtectionActiveattribute is also set to TRUE for trail S. The rerouted trail passesfrom node A to node B, C and D.:

FIG. 13B shows the topology model after reservation, where the originalpath is shown in patterned gray and the protection trail S is shown inlight gray. In this model, as the restored trail has a new TrailId butthe same Callid, the TTP TrailID is also set to 3. The CTPs that havebeen reused have a ReferenceCount=2, and they only point to their mostrecent SNC (i.e. knowledge of the original SNC is not kept by the CTP),as shown for SNC-D. The SNCs from the original trail P continue to referto their CTPs even if they have been reused (i.e. the original SNCs areessentially unaware of the trail S).

The protection trail always creates SNCs between its CTPs, even if thetwo CTPs already have an SNC created from the original trail. Thismaintains independence between the original and secondary trails,enabling easy reversion and easy re-dialing of the trail S, should italso fail.

The R&S control 12 now sends an ActivateTrail( ) to the NCC as before,the only difference being that no explicit regenerators are included atnode C in this example, although one could be selected by NCC.

The traffic on failed trail P has now been restored with over trail S(protection trail).

FIG. 13B shows how to revert the traffic from the secondary path S trailto its original path P. Let's say that once the troubled link4 has beenfixed, the operator decides to revert the connection to its originalpath P. The following steps will occur:

A ConnectionRevert( ) action is sent from the NOS to the R&S control.The request contains the CallId and the original TrailId. This isbecause it is possible that both trails P and S of the call have failedand been re-dialed, hence the specification of both Call Id and Trail Idare needed at the R&S control.

The R&S control 12 then deactivates trail S by sending aDeactivateTrail( ) command to the NCC 14, passed to all CTPs that makeup trail S.

The NCC will command all associated switch controllers to delete thecross connection objects associated with trail S. The cross connectionreference(s) in the subnetwork connections SNC are set to NULL.

The R&S control 12 then un-reserves the CTPs associated with the SNCs bydecrementing the ReferenceCount by one and setting the SNC associationto NULL. If the ReferenceCount equals 0, then the CTP UsageState ischanged to FREE. In this example, the ReferenceCount is 1, so theUsageState is still ACTIVE.

The R&S control 12 then deletes all SNCs associated with the trail S.

The R&S control 12 sets the StandbyTrailRef in the Trail to NULL and aProtectionActive attribute to FALSE. Trail S has now been completelyremoved.

The R&S control 12 must now check and re-establish the association fromthe CTP to SNC. That is, the SNC still refers to the original CTPs, butthe CTPs may have been re-used by trail S, so their SNC references mustbe restored. It is possible to design the CTP reservation mechanism sothat the previous SNC pointer is remembered in the CTP and automaticallyrestored upon un-reserve.

Once the CTP references have been restored, the trail will be in itsoriginal reserved state.

Any explicit regenerators are restored in the NE model, by issuing a“reserve” action on the appropriate regenerator pool and the Trail Idused as the reservation id.

The R&S control 12 can now send the ActivateTrail( ) request to the NCC14, specifying all parameters that were specified in the originalactivate request

When the NCC returns a successful response, the control plane returns asuccessful ConnectionRevertResponse( ) to the NOS. The original trailhas now been reverted.

1. In an agile optical network having a plurality of interconnectedswitching nodes, an object-oriented network information model,comprising: a core network information model that is common to allapplications requiring the information provided by said model, the modelfurther comprising, a network element (NE) information model comprisinga plurality of managed objects MOs, a MO including specific NE data thatdefine network implementation details; and a topological informationmodel comprising a plurality of topology objects TO, a TO includingspecific topological data for defining a trail established within saidnetwork, wherein said NE data does not include any topological data,said specific topological data does not include any NE data; and anextension to said core network information model for serving specificapplication areas.
 2. A network information model as claimed in claim 1,wherein all objects in said network information model use a universalobject description language.
 3. The object-oriented network informationmodel in claim 1, wherein said NE information model and said topologicalinformation model are bridged by a minimal number of inter-modelassociations for fully describing said trail.
 4. The object-orientednetwork information model as in claim 3, wherein said inter-modelassociations include: an association between a connection terminationCTP topology object and a CTP managed object; an association between asubnetwork or access group topology object and a NE object; and anassociation between a subnetwork connection topology object and a NEcross-connection object.
 5. The object-oriented network informationmodel as in claim 1 wherein the NE information model is further definedby a list with the classes of all MOs it contains, affects, supports andinherits from, for modeling the NEs that implement said network andspecifically not to model connections across said network in which saidNE participates, said NE information model further comprising: anequipment holder class, containing k equipment holder MOs; an equipmentclass containing I equipment MOs, each containing m software objects,and inheriting from one of an equipment holder object and a circuit packobject; and a termination point class, containing n termination pointobjects, each inheriting from one of a trail termination point TTPobject that specifies a potential termination of an optical path and aconnection termination point CTP object that specifies a potentialtermination of a connection.
 6. The object-oriented network informationmodel as in claim 5, wherein said equipment holders are hierarchicallyclassified at bay, shelf and slot level.
 7. The object-oriented networkinformation model as in claim 5, wherein a list associated with acircuit-pack object provides all affected by CTP objects available forsaid circuit pack object, while a list associated with a CTP objectprovides said circuit pack object that it is supported by said CTPobject.
 8. The object-oriented network information model as in claim 5,wherein the NE information model further comprises a fabric class with pfabric objects, wherein a fabric object contains a cross-connectionclass with q cross-connection objects, and a topology pool class TpPoolwith rTpPool objects.
 9. The object-oriented network information modelas in claim 8, wherein said MOs are auto-created upon connection of saidrespective network entity to said agile optical network.
 10. Theobject-oriented network information model as in claim 8, wherein aTpPool object inherits from a regenerator pool class and an access pooiclass.
 11. The object-oriented network information model as in claim 5,wherein said circuit pack object contains a port class for allowingmodeling of physical inter-card connections.
 12. The object-orientednetwork information model as in claim 11, wherein a port object isreferenced using an upstream-downstream pointer created using a tracechannel provided along all fiber connections in said agile opticalnetwork.
 13. The object-oriented network information model as in claim11, wherein a trace CTP object locates an associated port object bylocating a respective circuit pack object containing said port objectfrom the supported by objects in said list, and searching the affectedby objects in said list.
 14. The object-oriented network informationmodel as in claim 1 wherein the layered topology information modelfurther comprises: a topological components class including layernetwork objects, access group objects, subnetwork objects, link objectsand link end objects; a transport entities class including trailobjects, subnetwork connection objects, and link connection objects; anda termination point class including trail termination point TTP objects,a TTP object for specifying the ends of a trail object and connectiontermination point CTP objects, a CTP object for specifying the ends of alink connection object.
 15. The object-oriented network informationmodel as in claim 14, wherein the topological objects in saidtopological component class are auto-created upon commissioning saidagile optical network.
 16. The object-oriented network information modelas in claim 14, wherein the topological objects in said transport entityclass are created when said trail is created and are deleted when saidtrail is removed.
 17. The object-oriented network information model asin claim 14, wherein said TTP object is included in an access groupobject and said CTP object is included in a link end object.
 18. Theobject-oriented network information model as in claim 14, wherein saidlayer network is one of an optical channel Och layer network fortransparently conveying user information along an optical path over anoptical channel, an optical multiplex section OMS layer network fortransporting a multi-channel signal along a fiber link, and an opticaltransmission section OTS layer network for transmitting saidmulti-channel signal along a fiber section.
 19. The object-orientednetwork information model as in claim 18, further comprising a physicalmedia Phy layer network for modeling a cable with a plurality of fibersections.
 20. The object-oriented network information model as in claim19, further comprising a conduit layer network for modeling a physicalconduit in which said cable runs.
 21. The object-oriented networkinformation model as in claim 14, wherein a subnetwork connection objectabstracts a plurality of subnetwork and link objects between two CTPs.22. The object-oriented network information model as in claim 14,wherein a trail object in a server layer is represented by a linkconnection object in a client layer by associating the TTPs of saidtrail object to two corresponding CTPs in said client layer.